HDFS-4676. Merging change 1466099 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1466102 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -138,6 +138,9 @@ Release 2.0.5-beta - UNRELEASED
     HDFS-3981. Fix handling of FSN lock in getBlockLocations. (Xiaobo Peng
     and todd via todd)
 
+    HDFS-4676. TestHDFSFileSystemContract should set MiniDFSCluster variable
+    to null to free up memory. (suresh)
+
 Release 2.0.4-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestHDFSFileSystemContract.java

@@ -46,6 +46,7 @@ public class TestHDFSFileSystemContract extends FileSystemContractBaseTest {
   protected void tearDown() throws Exception {
     super.tearDown();
     cluster.shutdown();
+    cluster = null;
   }
 
   @Override